This invention relates to radar apparatus.
Modern marine radar apparatus is required to be highly versatile in order to provide the user with the clearest information about his surroundings. Many different features are commonly available. For example, the radar display can be presented in different ways: north up; course up; or heading up. The range displayed is often adjustable so that a relatively short range is represented when the vessel is entering or leaving port, or navigating a narrow passage, whereas a longer range is displayed when the vessel is in open waters. Heading vectors of the radar carrying vessel can be displayed to indicate future course, whereas trails can be displayed to indicate the vessel's previous track. Potential collision risks can be identified and tracked with information provided on the display as to the closest point of approach between the two vessels. This display can be switchable between different antennas and usually has several adjustable parameters such as gain, sea clutter, rain clutter, contrast, brilliance and so on. Additional information can be superimposed on the display such as stored maps of the area being navigated.
This multiplicity of features leads to apparatus of high complexity and requires the apparatus to have a large number of dedicated keys, switches or knobs etc. to control the many different functions. Accordingly, the apparatus is often difficult to use and requires a considerable period of use before the operator is familiar with its operation. This problem is aggravated by the fact that apparatus on different vessels may be from different manufacturers and have different layouts and by the fact that radar operators often move frequently from vessel to vessel.